Process of spinning viscose containing thiodiglycol



United States Patent O PROCESS OF SPINNING VISCOSE CONTAININ THIODIGLYCOL No Drawing. Application September 6, 1955 Serial No. 532,799

Claims priority, application France September 3, 1954 2 Claims. (CI. 18-54) This invention relates to the production of regenerated cellulose textile materials, and particularly filaments,

yarns, threads and the like.

Considerable research has been directed to the produc-.

tion of such materials having a very high tenacity, good elongation, a low degree of swelling in water and a good wet strength, and this research has been expanded by the need for such materials as reinforcing fibres for pneumatic tyres.

Originally the research was primarily directed to the method of stretching the yarns and like materials but more recently it has become known that the chemical phenomena which occur in the production of the viscose and its spinning can strongly affect the results obtained. In particular it has been found that the filaments are heterogeneous, having a skin structure different from that of the core of the filament, and that the thickness of the skin has an important influence on the properties of the materials obtained.

It is a principal object of 'the present invention to provide a process for the production of artificial filaments and the like ofregenerated cellulose having improved characteristics. A

A spinning solution for use in the spinning of filaments and the like comprises viscose solutions containing a thio compound of the general formula:

where R represents a grouping of the formula -'CH CH -OR3 and R 'represents a hydrogen atom or a grouping of the formula --CH -CH -OR where R, is a hydrogen atom or an alkyl or aryl group. Preferably where R is'not a hydrogen atom it is a lower alkyl group (i.e. containing up m4 carbon atoms).

The proportion of said thio compound may vary but is preferably 0.2 to 10% by weight of the alpha cellulose content of the viscose. The viscose is preferably of a low degree of ripeness, having a salt index greater than 7 and preferably 1 O-l5, as determined in accordance with the disclosure in the Brandenberger Patent No. 1,544,631, these conditions normally being associated with a 7- value of 48 to 65.

According to this invention a process for the production of regenerated cellulose filaments and the like comprises spinning a viscose containing a thio compound as just set forth into a Muller type coagulating bath (i.e. a bath containing sulphuric acid and a quantity of sodium sulphate in excess of any bisulphate formed), and stretching the filaments or the like continuously with their production.

It is advantageous to employ a long path of travel of the spinning filaments during the coagulation treatment, e.g. 6 metres or more. This long path may be obtained for example by the use of suitable guides or guide rollers. It is not essential for the yarn to be in contact in the coagulating bath during the whole of its fixing stage; it may be caused repeatedly to leave and reenter the coagulating bath.

The coagulating bath preferably has a high content of divalent or polyvalent metal salts; thus for example it may contain 30 g./litre of zinc sulphate or equivalent amounts of iron sulphate or nickel sulphate.

The stretching of the filaments should be effected while they travel through the coagulating path and should be as smoothly progressive as possible. If desired the filaments may be subjected to a separate stretching operation, continuously with their production, while passing through a second bath containing a hot aqueous medium e.g. a liquid medium, or through a steam-filled tube.

By means of the aforesaid process yarns are obtained which have (as compared with yarns obtained under similar conditions but from viscoses not containing the thio compound) a secondary swelling (i.e.-after finishing and drying) reduced'by 10 to 20%, a primary swelling,

after simple washing of the acid yarn, very close to the secondary swelling, smoother and less indented sections,

a thicker skin, an increase in tenacity, usually of the order of 10% or more, without reduction in elongation (and accordingly an increase of 10% or more in the silk factor) and improved wet strength. The silk factor is the product of the tenacity in grams per denier and the percentage elongation at breaking point.

The following examples will serve to illustrate the invention but are not to be regarded as limiting it in any way.

EXAMPLE I 1 A cellulose pulp containing 96% of a-cellulose is steeped in 18% caustic soda at 21 C. for 45 minutes and is then pressed to a weight corresponding to 2.8 times the weight of the a-cellulose. The alkali cellulose is ripened in known manner to produce (at the end of the process) a viscose spinning solution having a viscosity of 6080 poises. The alkali cellulose is xanthated with 38% of carbon disulphide at 25 C., and the Xanthate is then dissolved in caustic soda solution to produce a viscose containing 7% of cellulose and 6% of caustic soda. It is filtered and degassed in the conventional manner.

2 g. of thiodiglycol per 100 g. of a-cellulose present (calculated as dry Weight) are added to the caustic soda solution used for dissolving the xanthate. I

The viscose obtained is spun at a salt index of 9 into a The holes, the supply of viscose being adjusted to give a final count of 400 denier.

The yarn is subjected to a progressive stretching up to 70% on a series of rollers and it is then collected in a centrifugal spinning pot and subjected to the conventional after-treatments.

EXAMPLE II A viscose is prepared in a manner similar to that of Example I, but the viscose has added thereto 6 g. of thiodiglycol per 100 g. of tat-cellulose (calculated on dry weight). The viscose is spun at a salt index of 12.5 into a bath containing, per litre, 110 g. of sulphuric acid, 350

. g. of sodium sulphate and 70 g. of zinc sulphate. The

spinning is effected at a temperature of 55 C. and the filaments are stretched 30% on rollers. The spinneret used has 200 holes.

The yarn is caused to travel 1 metre through a bath containing 10 grams/ litre of sulphuric acid and having a temperature of -98 C. In this bath, it is stretched by a further 50%, giving a total stretching of the supply of viscose to the spinneret being at a rate so as to ensure a final count of 400 denier.

The yarn is collected in a centrifugal spinning pot and then treated in the usual manner.

- Patented Nov. 10,

The 400 denier yarns obtained in the foregoing examples have been conditioned at 20 C. and a relative humidity of 65% and have been compared with comparison yarns obtained under the same conditions but without adding the thio compounds to the viscose. The serimetric characteristics and the degrees of swelling are set out in the following table.

The products of the invention possess remarkable properties of resistance to repeated washing, and are eminently suitable for the manufacture of staple fibres, for which purpose, large bundles of spun filaments are cut in manner known per se.

We claim:

1. A process for the production of regenerated cellu- Table Dry Wet Swelling Amounts of product added Silk in g. per 100 g. of a-cellulose Tenacity, Elonga- Tenacity, Elonga- Factor Secondg./den. tion, g./den. tio Primary ary percent percent Ex. I:

Stretchlnginthe coagu- 0 2.96 26.5 2.50 34.5 78.4 100 91 lation bath 2 3.40 2&1 2. 48 36.7 88.0 76 74 'sii iementar stretch- 0 s. 20.9 2.150 27.4 67 as 84 in at 90 C 6 3. 70 20. 8 2. 10 26. 7 77. 0 72 71 The thread obtained in accordance with Example I lose filaments which comprises spinning intoa coagulating has a structure very different from that of the comparison bath containing about 110 grams per liter of sulphuric thread, the proportion of the skin with respect to the total acid, about 250 to 350 grams per liter of sodium sulphate, section being much greater. The thread obtained in EX- and about to 70 grams per liter of zinc sulphate a spinample II has the same very characteristic bean-like crossning solution comprising viscose containing thiodiglycol section and is almost entirely constituted by the compact in the proportion of 0.2 to 10% by weight of the a-cellustructure characterising the skin. 30 lose content of the solution, and stretching the filaments The yarns obtained according to the present invention obtained continuously with their production. are particularly suitable for use in the manufacture of 2.. A process for the production of regenerated cellucords for the reinforcement of tyres, these cords having lose filaments which comprises spinning into a coagulating a higher breaking strength and a better resistance to bath containing about 110 grams per liter of sulphuric repeated dynamic stresses. acid, about 250 to 350 grams per liter of sodium sulphate, To produce a cord for this purpose, the yarn obtained and about 30 to 70 grams per liter of zinc sulphate a in Example 11 may be subjected, while moist to a stretchspinning solution comprising viscose containing thiing of 8.5% between rollers, and then dried without tenodiglycol in the proportion of 0.2 to 10% by weight of sion. The yarn obtained is used for the manufacture of the a-cellulose content of the solution, the said solution a cord by assembly of 9 ends each of 400 denier. The having a salt index greater than 7, and stretching the comparison yarn, after being subjected to the same stretch filaments obtained continuously with their production. treatment, is also similarly converted into a cord.

The characteristics of the cords obtained are as follows: fer n es Cited in the file of this patent UNITED STATES PATENTS ps Breaking Rupture 2,535,044 Cox Dec. 26, 1950 Dry giggle? tt ilif iilvigriiillrs, 2, M rin Apr. 22, 1952 count W7 kg @611 2,664,360 Charles et al. Dec. 19, 1953 y 2,732,279 Tachikawa Jan. 24, 1956 2,775,505 Pedlow Dec. 25, 1956 figlfi fillillliififfiiji Z1253 i312 15. 3 131283 2,777,775 Edwards Jan. 15, 1957 2,852,334 Hollihan et a1. Sept. 16, 1958 

1. A PROCESS FOR THE PRODUCTION OF REGENERATED CELLULOSE FILAMENTS WHICH COMPRISES SPINNING INTO A COAGULATING BATH CONTAINING ABOUT 110 GRAMS PER LITER O FSULPHURIC ACID, ABOUT 250 TO 350 GRAMS PER LITER OF SODIUM SULPHATE, AND ABOUT 30 TO 70 GRAMS PER LITER OF ZINC SULPHATE A SPINNING SOLUTION COMPRISING VISCOSE CONTAINING THIODIGLYCOL IN THE PROPORTION OF 0.2 TO 10% BY WEIGHT OF THE A-CELLULOSE CONTENT OF THE SOLUTION, AND STRETCHING THE FILAMENTS OBTAINED CONTINUOUSLY WITH THEIR PRODUCTION. 